Calculating Thermal Energy Changes in Phase Changes

Mr. Melis explains thermal energy changes during phase transitions in a three-part series. In this video, he focuses on calculating energy changes for single phase transitions, using two examples: water vapor condensing to water and ice melting to water. Each example involves multiple steps, including calculating energy release or absorption using specific heat capacity and heat of vaporization or fusion. The video concludes with a summary and a prompt to subscribe.

What is the initial temperature of the water vapor in the first example problem?

• 100 degrees Celsius

• 105 degrees Celsius

• 15 degrees Celsius

• 35 degrees Celsius

What is the condensation point of water?

• 100 degrees Celsius

• 150 degrees Celsius

• 0 degrees Celsius

• 50 degrees Celsius

Tags

NGSS.MS-PS1-4

Which formula is used to calculate the thermal energy released by water vapor as it cools from 105 to 100 degrees Celsius?

• Q = mcΔT

• Q = cmΔT

• Q = mL

• Q = mΔH

What is the specific heat capacity of water vapor used in the calculations?

• 1.0 J/g°C

• 2.0 J/g°C

• 3.0 J/g°C

• 4.18 J/g°C

How much energy in kilojoules is released when 35 grams of water vapor condenses into water?

• -91.9 kJ

• -12.4 kJ

• -35.0 kJ

• -79.1 kJ

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What is the final temperature of the water in the first example problem?

• 25 degrees Celsius

• 0 degrees Celsius

• 15 degrees Celsius

• 100 degrees Celsius

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

In the second example, what is the initial temperature of the ice?

• 12 degrees Celsius

• 25 degrees Celsius

• 0 degrees Celsius

• -12 degrees Celsius

Tags

NGSS.MS-PS1-4

What is the specific heat capacity of ice used in the calculations?

• 2.03 J/g°C

• 4.18 J/g°C

• 3.0 J/g°C

• 1.0 J/g°C

Tags

NGSS.MS-PS3-3

How much energy in kilojoules is absorbed when 95 grams of ice melts into water?

• 2.3 kJ

• 9.9 kJ

• 43.9 kJ

• 31.7 kJ

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What is the final temperature of the water in the second example problem?

• 100 degrees Celsius

• 12 degrees Celsius

• 25 degrees Celsius

• 0 degrees Celsius

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4